Silicon-Vacancy Spin Qubit in Diamond: A Quantum Memory Exceeding 10 ms with Single-Shot State Readout

Area of Science:

• Quantum physics
• Solid-state quantum systems
• Quantum optics

Background:

• The silicon-vacancy (SiV-) color center in diamond is a promising quantum system.
• Its optical transitions are suitable for quantum photonics and nanophotonic devices.
• Previous SiV- spin coherence times were limited by phonon interactions.

Purpose of the Study:

• To improve the spin coherence time of SiV- centers.
• To suppress phonon-induced dephasing in SiV- spin qubits.
• To establish SiV- centers as viable solid-state qubits for quantum networks.

Main Methods:

• Operating SiV- centers at cryogenic temperatures (below 500 mK).
• Utilizing spin-conserving optical transitions by aligning magnetic fields.
• Applying microwave fields for coherent spin control.
• Achieving single-shot spin readout.

Main Results:

• Phonon-induced dephasing suppressed by 5 orders of magnitude.
• Single-shot spin readout fidelity of 89% achieved.
• Spin coherence time (T2) of 13 ms demonstrated.
• Spin relaxation time (T1) exceeding 1 s at 100 mK.

Conclusions:

• SiV- centers exhibit significantly improved spin coherence at low temperatures.
• Coherent control and readout are feasible, enabling quantum applications.
• SiV- centers are a leading solid-state platform for quantum network development.